1. Field of the Invention
This invention relates to a method of grinding a workpiece having plural cylindrical portions to be ground, and more specifically, relates to a method of grinding a workpiece having plural cylindrical portions with plural grinding wheels, wherein the plural cylindrical portions of the workpiece are ground using a work rest for supporting one or more cylindrical portions.
2. Prior Art of the Invention
In general, a grinding machine having plural grinding wheels 1A-1F is used to simultaneously grind plural journal portions 2A-2F of a workpiece 2, as shown in FIG. 1. In such grinding machine, the workpiece 2 is deformed, as shown in FIG. 1, when all of the grinding wheels 1A-1F contact the journal portions 2A-2F of the workpiece 2, because of the large grinding force acting upon the workpiece 2. Therefore, in such grinding machine, work rests 3 are installed to support one or more journal portions, for example, the two journal portions, 2B and 2E.
However, in such grinding machine, the grinding accuracy is deteriorated when the journal portions 2B and 2E to be supported by the work rests 3 have been machined inaccurately in previous machining such as the cutting operation using a lathe. Namely, if the journal portions 2B and 2E have distorted outer surfaces, the positions of the center of the journal portions 2B and 2E irregularly changes, because of the contact between the distorted outer surfaces of the journal portions 2B and 2E and the work rests 3 during rotation.